The objective of this research proposal is to increase knowledge of the structure and function of the macromolecular components present in human parotid saliva, as well as their importance in the maintenance of oral health. Studies will be focused on a group of basic proline-rich proteins and glycoproteins which are wide-spread and abundant in salivary secretions of human and other species. Major emphasis of the proposal will be placed in the determination of the biological function(s) of these proteins. Interactions of these serous products with other salivary secretory products will be investigated by testing the ability of the basic proline-rich proteins to interfere with the binding of fluorescent hydropholic probes to salivary mucins, and by continued study of their effect in the rheological properties of mucins. Another goal of this proposal is the determination of the primary structures of several basic proline-rich proteins and glycoproteins, some of which are phosphorylated. Enzymatic and chemical deglycosylation of the glycoproteins will be used to obtain protein cores for sequence analysis. The non-glycosylated proteins and the proteins cores will be digested with clostripain or trypsin to obtain large fragments for sequencing. From these analyses, information as to the relationship of these proteins to each other and to other salivary proline-rich proteins, will be obtained.